Filling tool

ABSTRACT

A filling tool is provided, for mating with an electrically conductive coupler having a tip extending therefrom. The filling tool comprises a housing, an electrically conductive valve stem disposed in and electrically isolated from the housing, and an electrically conductive contact extending from the valve stem that is biased and axially movable. An electrical circuit is completed through the filling tool and the coupler by contact between the tip of the coupler and the contact on the valve stem.

FIELD OF THE INVENTION

The invention relates to a filling tool, and more particularly to a filling tool that detects a mating coupler for automatic attachment of the filling tool to the mating coupler and for detection of disconnection of the filling tool from the mating coupler.

BACKGROUND OF THE INVENTION

In the air conditioning and vehicle manufacturing industries, there is a need to fill systems with refrigerant. In existing systems a male coupler is provided on the system. A typical coupler 100 is shown in FIG. 1. The coupler 100 has a channel for filling and/or evacuating the system to which it is attached. A tip 106, which is biased forward by a coupler spring 102, extends from the coupler 100, and can be the end of a valve stem disposed in the coupler. A circumferential groove 104 is formed in an outside surface of the coupler. A filling tool is configured to sealingly mate with the male coupler and engage the coupler by axially displacing a tapered cam toward the male coupler, locking a set of bearings into the groove in the coupler. The tool is manually aligned to the male coupler, then, while holding the tool in place, an operator actuates a solenoid or a pneumatic/hydraulic piston to displace the cam, mating the filling tool to the male coupler.

Refrigerant is charged into the system under pressure. Thus, if the tool is not properly engaged on the coupler, the tool will be forced off of the coupler, discharging refrigerant into the environment, creating an environmental and safety problem. Some filling tools have a proximity switch that detects the position of a trigger for activating the collar or the position of the collar itself corresponding to the displacement consistent with proper engagement of the collar to the coupler. However, false readings are possible due to the limitations of the proximity switch, and frequent maintenance is required to maintain such systems.

A need exists for a filling tool that can connect with a typical coupler and accurately detect the connection status of the tool and the coupler. Furthermore, it is desirable to have a filling tool which can automatically attach to the coupler when the tool is aligned with the coupler.

SUMMARY OF THE INVENTION

A filling tool is provided, for mating with an electrically conductive coupler having a tip extending therefrom. The filling tool comprises a housing, an electrically conductive valve stem disposed in and electrically isolated from the housing, and an electrically conductive contact extending from the valve stem that is biased and axially movable. An electrical circuit is completed through the filling tool and the coupler by contact between the tip of the coupler and the contact on the valve stem. Completion of the electrical circuit either triggers automatic actuation of a piston attached to a tapered cam for locking a plurality of ball bearings in disposed in the filling tool into a locking groove in the coupler for attaching the filling tool and coupler together, or enables displacement of the valve stem, or both.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example with reference to the accompanying figures of which:

FIG. 1 is a longitudinal sectional view of a typical coupler used for evacuating and charging an air conditioning system;

FIG. 2 is a longitudinal sectional view of a filling tool according to an exemplary embodiment of the present invention;

FIG. 3 is a longitudinal sectional view of the filling tool of FIG. 2 and the coupler of FIG. 1 in an aligned state with a slide cam and a valve stem in a non-actuated state;

FIG. 4 is a longitudinal sectional view of the filling tool of FIG. 2 and the coupler of FIG. 1 with the slide cam in an actuated state and the valve stem in a non-actuated state;

FIG. 5 is a longitudinal sectional view of the filling tool of FIG. 2 and the coupler of FIG. 1 with the slide cam and the valve stem in an actuated state; and

FIG. 6 is a detailed sectional view of a valve stem of the filling tool of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 2-6 show a filling tool for mating with an electrically conductive coupler with a tip extending from the coupler, according to an exemplary embodiment of the invention. The filling tool 1 comprises a housing 3, and an electrically conductive valve stem 2 disposed in and electrically isolated from the housing 3. In an exemplary embodiment, the housing 3 comprises a cylinder 8, a front cartridge 4, and a rear cartridge 6. The filling tool 1 is generally cylindrical and has an axis, with a front direction F and a rear direction R in opposing directions along the axis. A rear cartridge 6 is disposed in the cylinder 8 at the rear R, and a front cartridge 4 is disposed in the cylinder 8 at the front F. The cylinder 8 and the cartridges 4, 6 may comprise a machinable metal suitable for use with the particular fluid to be used, for example, stainless steel or aluminum. The cylinder 8 has a high-precision bore for receiving the front and rear cartridges 4, 6. As shown in FIG. 2, the bore may be stepped to accommodate a rear cartridge 6 having a smaller diameter and a front cartridge 4, having a greater diameter. Seals, such as o-rings may be used to seal the cartridges 4, 6 to the inside bore of cylinder 8. A collar 36 is attached inside of the front cartridge 4, such as by threaded engagement between internal threads in the front cartridge 4 and external threads on the collar 36. A plurality of ball bearings 34 are retained in the collar 36, such that they can move in a radial direction.

The cartridges 4, 6 are generally cylindrical in shape, having an outside diameter sized to precisely fit in the bore of the cylinder 8 and an inside diameter sized to receive the valve stem 2 in a precisely fitting manner, allowing for guided axial movement of the valve stem 2 inside of the cartridges 4, 6.

The valve stem 2 has a generally tubular shape, with an outside diameter precisely sized to be slidingly received in the inside diameters of the cartridges 4, 6. The valve stem comprises an electrically conductive material, such as stainless steel. The sliding engagement is provided through electrically insulating seals, such as a REV-O-CAP, available from C.E. Conover & Co., Inc. of Bensalem, Pa. A valve stem flange 7 is disposed on the valve stem 2 intermediate a front end and a back end, thereof. A tip 5 is disposed on an end of the valve stem 2 extending in the direction of the front end F of the tool 1. The tip 5 has a smaller diameter than the valve stem 2 and is sized and configured to transfer axial force with the tip 106 on the coupler 100.

In an exemplary embodiment, as shown in FIG. 6, the tip 5 comprises a solid base 51 and a contact housing 52. The base 51 is attached to the valve stem 2 and the contact housing 52 is attached to the base 51, by, for example, threaded engagement. A contact housing flange 53 extends radially inward from the contact housing 52 at the front end F. A contact 54 is disposed in the contact housing 52 and is axially movable therein. The contact 54 is hat-shaped having a flat top 55 for contacting the tip 106 of the coupler 100, a tube 56 extending from the top and a contact flange 57 disposed inside the contact housing 52 for interfering with the contact housing flange 53 to hold the contact 54 in the contact housing 52. A front contact spring 58 is disposed in the contact housing 52 and the contact 54, biasing the contact 54 in the direction of the front end F of the filling tool 1. In an exemplary embodiment, the front contact spring 58 is a helical compression spring.

An annular gap is disposed inside of the cylinder 8, between the front cartridge 4 and the rear cartridge 6 in the axial direction for receiving the valve stem flange 7. The outside diameter of the annular gap is defined by an insulating sleeve 12. The annular gap is defined in the direction of the rear end R by a rear washer 24, and in the direction of the front end F by a front washer 22. The insulating sleeve, the rear washer 24, and the front washer 22 are comprised of an insulating material capable of carrying a spring load, such as Ultra-High Molecular Weight polypropelene (UHMW). The valve stem flange 7 is biased in the direction of the rear end R by a rear contact spring 26. The rear contact spring 26 is a helical compression spring abutting the valve stem flange 3 at one end, in the direction of the rear end R, and a conductive washer 21 adjacent the front washer 22 at the other end, in the direction of the front end F. Thus, the valve stem 2 is biased in the direction of the rear end R, and is electrically isolated from the housing by the insulating sleeve 12, the front washer 22 and the rear washer 24. Conversely, the valve stem 2 is electrically connected to the conductive washer 21, which may, for example, comprise brass. The conductive washer 21 is connected to a ring terminal 18, disposed outside of the housing 3. A nylon spacer 20 may be used to electrically isolate the ring terminal 18 from the housing 3.

A piston 10 is slidingly disposed on the housing toward the front end F. In the exemplary embodiment shown in FIGS. 3-5, the piston 10 has a stepped bore that slides on the outside diameter of the front cartridge 4 at the smaller bore and on the cylinder 8 at the larger bore. A slide cam 14 is attached to the piston 10, such as by threaded engagement. The slide cam 14 is generally tubular in shape with a tapered inside diameter that is greater in the direction of the front end F and smaller in the direction of the rear end R. The slide cam 14 extends over the collar 36.

In operation, the filling tool 1 is aligned with the coupler 100, such that the outside diameter of the coupler 100 enters the inside diameter of the collar 36. The outside diameter of the coupler 100 has a taper on it to press the ball bearings 34 in the collar 36 radially outward. The coupler 100 is advanced until the tip 106 of the coupler 100 comes into contact with the flat top 55 on the contact 54 of the filling tool 1. This contact between the contact 54 of the filling tool 1 and the tip 106 of the coupler 100 closes a sensing circuit. The sensing circuit runs from a power supply (not shown) through a wire (not shown) to the housing 3 of the filling tool 1, to the coupler 100, through the coupler (from the outside diameter that is in contact with the collar 36 of the filling tool, to the coupler spring 102, to the tip 106), to the contact 54 of the filling tool, through the valve stem 2 to the flange 3, to the rear contact spring 26, to the conductive washer 21, to the ring terminal 18, to a wire 19, to a sensor (not shown) which senses current passing through the circuit to indicate that the coupler 100 is in a mated position relative to the filling tool 1.

In an exemplary embodiment of the invention, the sensor is used to trigger a pneumatic valve which activates the piston 10 driving the slide cam 14 over the ball bearings 34. The taper on the inside opening of the slide cam 14 drives the balls 34 radially inward. The dimension from the contact 54 to the ball bearings 34 is controlled in the filling tool 1 to correspond to the distance between the tip 106 and the locking groove 104 of the coupler. Prior to contact being made between the tip 106 of the coupler 100 and the contact 54 of the filling tool, both the piston 10 and the valve stem 2 are in a non-actuated state. Then, when the contact 54 contacts the tip 106, the sensing circuit is closed, the piston 14 is actuated, and the ball bearings 34 that are aligned with the locking groove are driven into the locking groove to lock the filling tool 1 to the coupler 100, as shown in FIG. 4.

In an existing filling tool, the coupler is advanced to a hard stop, then an operator manually activates the slide cam. In the present invention, there is a reduced risk of activating the slide cam 14 when the ball bearings 34 of the filling tool 1 are not properly aligned with locking groove 104. This is because the present invention does not rely on an operator to assure the positioning of the filling tool 1, but rather the alignment is constructed into the filling tool 1. Moreover, if the ball bearings 34 were not properly aligned with the locking groove 104, the coupler 100 would be driven back, breaking the contact between the tip 106 of the coupler 100 and the contact 54 of the filling tool 1, thereby breaking the sensing circuit. Therefore, the filling tool can be designed to prevent opening a filling valve when the sensor does not sense current in the sensing circuit.

After the filling tool 1 and the coupler 100 are locked together, a second pneumatic valve (not shown) is opened to drive the valve stem 2 in the forward direction F, allowing refrigerant to flow through the filling tool 1 into the coupler 100, as shown in FIG. 5. In an exemplary embodiment of the invention, the sensor sends a control signal to a controller, such as a programmable controller, operatively associated with a pneumatic valve, which enables the valve stem 2 to be actuated.

In an exemplary embodiment, the valve stem 2 in the filling tool 1, the tip 106 in the coupler 100 and the front contact 54, are all spring biased. It is important that the springs are selected such that the contact 54 is displaced by a contact force that is substantially less than the force required to displace the tip 106 of the male coupler 100 or the force required to displace the valve stem 2. Thus, as the filling tool 1 is advanced onto the coupler 100, the spring 58 in the contact 54 and the contact housing 52 of the filling tool 1 is displaced first creating a positive electrical contact and closing the sensing circuit, while the tip 106 of the coupler and the valve stem 2 are not displaced. The valve stem 2 and the tip 106 are then displaced by a separate operation, such as opening a second pneumatic valve, that drives the valve stem 2 in the forward direction F, and also displacing the tip 106 of the coupler 100 through the contact 54 and the contact housing 52.

The foregoing illustrates some of the possibilities for practicing the invention. Many other embodiments are possible within the scope and spirit of the invention. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range of equivalents. 

1. A filling tool, for mating with an electrically conductive coupler with a tip extending therefrom, the filling tool comprising: a housing; an electrically conductive valve stem disposed in and electrically isolated from the housing; and an electrically conductive, biased, movable contact extending from the valve stem; wherein an electrical circuit is completed by contact between the tip of the coupler and the contact on the valve stem.
 2. The filling tool of claim 1, wherein: the coupler has a circumferential ball lock groove; a collar is attached to the housing having radially movable ball bearings disposed therein; a slide cam is disposed on and movable relative to the housing and collar, the slide cam having a tapered inside diameter; and the electrical circuit comprises a current sensor, wherein completing the circuit triggers the current sensor, which automatically actuates the slide cam, such that the tapered inside diameter forces the ball bearings into the locking groove, attaching the filling tool to the coupler.
 3. The filling tool of claim 1, wherein the electrical circuit comprises a current sensor, and completing the circuit triggers the current sensor, which enables the valve stem to be actuated.
 4. The filling tool of claim 1, wherein an annular cavity is formed in the housing and the valve stem has a flange disposed in the annular cavity.
 5. The filling tool of claim 4, wherein the flange is pneumatically actuated to open a valve in the coupler.
 6. The filling tool of claim 5, wherein the valve stem is actuated by a controller and the controller is enabled by the sensor only when the contact is in contact with the tip of the coupler.
 7. A refrigerant filling system for filling and evacuating a refrigerant system through a coupler having a tip extending therefrom and a circumferential ball lock groove thereon, the filling system comprising: a filling tool with a housing and an electrically conductive valve stem disposed in and electrically isolated from the housing; and an electrically conductive, biased, movable contact extending from the valve stem; wherein an electrical circuit is completed by contact between the tip of the coupler and the contact on the valve stem.
 8. The refrigerant filling system of claim 7, further comprising: a collar attached to the housing and having a plurality of ball bearings disposed therein in a radially movable manner; a piston axially slidable on the housing; a tapered cam attached to the piston; and a controller that automatically actuates the piston when the electrical circuit is completed to axially move the tapered cam and lock the ball bearings in the ball lock groove.
 9. The refrigerant filling system of claim 7, wherein the electrical circuit comprises a current sensor, and completing the circuit triggers the current sensor.
 10. The refrigerant filling system of claim 9, further comprising a controller operatively connected to the sensor which enables the valve stem to be actuated when the sensor is triggered.
 11. A method of automatically attaching a filling tool to a coupler with a tip extending from the coupler and a locking groove formed in the coupler, comprising the steps of: applying a circuit with a voltage potential between a housing of the filling tool and an electrically isolated valve stem with a forward biased movable contact at a front tip of the valve stem, with a current sensor on the circuit; setting a distance between the contact and a plurality of radially movable ball bearings in the filling tool to correspond to a distance between the tip and ball lock groove of the coupler; advancing the filling tool over the coupler until the contact comes into contact with the tip of the coupler, thereby closing the circuit; and automatically actuating a sliding cam in a forward direction when current is sensed by the sensor, to radially displace the ball bearings, locking them into the locking groove.
 12. A method of sensing that a filling tool is attached to a coupler with a tip extending from the coupler, comprising the steps of: applying a circuit with a voltage potential between a housing of the filling tool and an electrically isolated valve stem disposed in the housing and having a forward biased movable contact at a front tip of the valve stem; and sensing when the circuit is closed.
 13. The method of claim 12, further comprising the step of: enabling the valve stem to be actuated only when the circuit is closed.
 14. The method of claim 12, further comprising the step of: automatically actuating a piston attached to a tapered cam when the circuit is closed. 